The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
In a typical motor vehicle, certain components have historically been fastened together, such as for example a differential ring gear and a differential carrier. The choice of fastening such components has historically been made due to the difference in materials of the two items. The ring gear is typically provided as a gear steel and the differential carrier, due to its complex geometry, is typically provided as cast iron. Attempts have been made to reduce the weight and assembly cost of this assembly by welding these two components together. Because of the physical and metallurgical property differences between these alloys, as the weld joint rapidly cools following welding, residual stresses at a joining line between the material of the first and the second components and therefore at the location of the weld root may induce weld joint cracking due to welding induced brittle metallurgical microstructure and residual stress, which normally initiates at the weld root and propagates along the ductile cast iron material weld heat affected zone (HAZ). The higher the base ductile iron strength, the more sensitive the weld joint is to develop weld root cracks in the ductile iron HAZ. Such weld root cracks may result in weld joint premature failure.
Accordingly, there is a need for a weld joint design that mitigates against weld root cracks and joint fracture when welding components with different metallurgical and physical properties.